spencer



(No Model.) 2 Sheets-Sheet 1.

*RQSPENOBR.

Pyrometr.

No. 235,389. I Patented Dec. 14,1880.

Kwmsmsx N PETERS, FHOTO-LITHOGRAFHER, WASHINGTON, D C.

(No Model.) '2 Sheets-Sheet 2.

R.ISQPBNOER. Pyrome'ter.

Patented Dec. 14,1880.

, -UN'ITED STATES PATENT OFFICE.

ROBERT SPENCER, OF BROOKLYN, NEW YORK.

PYROMETER.

SPECIFICATION formingpart of Letters Patent No. 235,389, dated December 14, 1880,

Application filed July 26, 1880. (No model.) Patented in Great Britain April 5, 1871.

To all whom. it may concern:

Be it known that I, ROBERT SPENCER, of

the city of Brooklyn, county of Kings, and

The highest registration that has beenhere tofore obtained without injury to the instrument used is 1,500 and this only by a temporary insertion and withdrawal of the instrument to prevent its destruction or injury.

My apparatus consists, generally, of a hollow vessel or crucible, preferably made of plumbago, and capable of resisting an extremely high degree of heat in a furnace or retort, and a piece of platinum, or platinum and iridium, or other expansible infusible metal, secured to the lower end of a hollow or solid rod of copper, brass, or other suitable material four or five feetin length, the lower end having the infusible shoe resting freely in the plumbago shield or crucible, and the upper end operating a gage or registering mechanism consistingof aneedle and a dial-plate suitably marked through intermediate gearing.

- In my drawings, Figure 1 represents an external view of a registering-gage; Fig. 2, a view of the index-moving mechanism; Fig.3, a cross-section of the crucible, showing the expansible rod and its protecting shoe or end; and Fig. 4, a view of a modification of my apparatus where it is desired to insert the pyroineter horizontally instead of vertically.

A represents a dial-plate and index-finger, which plate, as shown, is graduated up to 4,000 Fahrenheit. It may be provided with a double dial or series of divisions, one indicating the temperature and the other the fusing or meltingpoints of different materials. I The mechanism for moving this index-finger may be of any suitable character, one form being shown in Fig. 2, in which the motion of the the expansion of the rod in the movement of the index-finger.

In Fig. 3 is shown the metallic rod E, the expansion of which is to be used to operate the dial. This rod E rests at one end against the registering mechanism, and at the other against the base of the infusible crucible F. This rod is protected from melting by contact with the crucible by a shoe or protector of in fusible metal, G, preferably platinum or iridium. The rod E is operated within adjustable tubes H K. The tube H, sliding within the tube K, may be set at any point bya set-screw, and thereby the adjustment of the apparatus is obtained.

It is obvious thatthe expanding metallic rod, being protected by an infusible crucible or outer shield, is not so liable to melt or be destroyed as when directly placed within the furnace, and likewise that all contact between said metallic rod and the crucible being prevented by the protecting-shoe Gr, any further liability of fusion at said point of contact is prevented. The result is that a pyrometer soconstructed will remain intact when subjected to any degree of heat insufficient to fuse the crucible, and can be left in the furnace, which is not the case with any other pyrometer with which I am acquainted. In case it is preferable to insert the crucible horizontally, and to carry up the registering-dial vertically, a bellcrank, L, may be inserted in the connection,as shown at Fig. 4. By means of this contrivance the registering-dial may be carried to any distance from the heat of the furnace, and said heat may be exactly measured at all times.

My invention must be distinguished from the pyrometers consisting wholly of vitreous materials, where the relative degrees of expansion are so slight that but little benefit can be derived from their use, and also from those \vhere outer metal cases are employed, capable i only of use where but comparatively low temperatures arc to be registered.

What I claim as my invention, and desire 5 to secure by Letters Patent, is-

1. A pyrometer operated by the expansion of metals, in which a metal rod connected to a registering device extends into and is protected from the heat of the furnace by a closed to surrounding crucible of refractory material,

substantially as set forth.

2. In apyrometerin which the indication is occasioned by the expansion of a metal, the combination, with a metal rod, of an infusible protecting crucible or cover of refractory material and an intermediate protecting cover or shoe arranged at the inner end of the rod, between the same and the crucible of refractory material, said shoe being composed of ahighlyint'nsible metal, substantially as set forth.

ROBT. SPENCER. Witnesses S. F. SULLIVAN, \VM. A. IoLLooK. 

